[MAC80211]: improved short preamble handling
Similarly to CTS protection, whether short preambles are used for 802.11b
transmissions should be a per-subif setting, not device global.
For STAs, this patch makes short preamble handling automatic based on the ERP
IE. For APs, hostapd still uses the prism ioctls, but the write ioctl has been
restricted to AP-only subifs.
ieee80211_txrx_data.short_preamble (an unused field) was removed.
Unfortunately, some API changes were required for the following functions:
- ieee80211_generic_frame_duration
- ieee80211_rts_duration
- ieee80211_ctstoself_duration
- ieee80211_rts_get
- ieee80211_ctstoself_get
Affected drivers were updated accordingly.
Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e76a586..b0af6e9 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -127,7 +127,6 @@
struct ieee80211_tx_control *control;
unsigned int unicast:1;
unsigned int ps_buffered:1;
- unsigned int short_preamble:1;
unsigned int probe_last_frag:1;
struct ieee80211_hw_mode *mode;
struct ieee80211_rate *rate;
@@ -286,6 +285,11 @@
unsigned int promisc:1;
unsigned int use_protection:1; /* CTS protect ERP frames */
+ /* use short preamble with IEEE 802.11b: this flag is set when the AP
+ * or beacon generator reports that there are no present stations that
+ * cannot support short preambles */
+ unsigned int short_preamble:1;
+
struct net_device_stats stats;
int drop_unencrypted;
int eapol; /* 0 = process EAPOL frames as normal data frames,
@@ -447,7 +451,6 @@
int fragmentation_threshold;
int short_retry_limit; /* dot11ShortRetryLimit */
int long_retry_limit; /* dot11LongRetryLimit */
- int short_preamble; /* use short preamble with IEEE 802.11b */
struct crypto_blkcipher *wep_tx_tfm;
struct crypto_blkcipher *wep_rx_tfm;
diff --git a/net/mac80211/ieee80211_ioctl.c b/net/mac80211/ieee80211_ioctl.c
index e7904db..8292431 100644
--- a/net/mac80211/ieee80211_ioctl.c
+++ b/net/mac80211/ieee80211_ioctl.c
@@ -1061,7 +1061,10 @@
break;
case PRISM2_PARAM_PREAMBLE:
- local->short_preamble = value;
+ if (sdata->type != IEEE80211_IF_TYPE_AP)
+ ret = -ENOENT;
+ else
+ sdata->short_preamble = value;
break;
case PRISM2_PARAM_STAT_TIME:
@@ -1184,7 +1187,7 @@
break;
case PRISM2_PARAM_PREAMBLE:
- *param = local->short_preamble;
+ *param = sdata->short_preamble;
break;
case PRISM2_PARAM_STAT_TIME:
diff --git a/net/mac80211/ieee80211_sta.c b/net/mac80211/ieee80211_sta.c
index 8e65489..0f5f813 100644
--- a/net/mac80211/ieee80211_sta.c
+++ b/net/mac80211/ieee80211_sta.c
@@ -318,6 +318,7 @@
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct ieee80211_if_sta *ifsta = &sdata->u.sta;
int use_protection = (erp_value & WLAN_ERP_USE_PROTECTION) != 0;
+ int preamble_mode = (erp_value & WLAN_ERP_BARKER_PREAMBLE) != 0;
if (use_protection != sdata->use_protection) {
if (net_ratelimit()) {
@@ -329,6 +330,18 @@
}
sdata->use_protection = use_protection;
}
+
+ if (!preamble_mode != sdata->short_preamble) {
+ if (net_ratelimit()) {
+ printk(KERN_DEBUG "%s: switched to %s barker preamble"
+ " (BSSID=" MAC_FMT ")\n",
+ dev->name,
+ (preamble_mode == WLAN_ERP_PREAMBLE_SHORT) ?
+ "short" : "long",
+ MAC_ARG(ifsta->bssid));
+ }
+ sdata->short_preamble = !preamble_mode;
+ }
}
@@ -415,6 +428,7 @@
ieee80211_sta_send_associnfo(dev, ifsta);
} else {
netif_carrier_off(dev);
+ sdata->short_preamble = 0;
sdata->use_protection = 0;
memset(wrqu.ap_addr.sa_data, 0, ETH_ALEN);
}
@@ -2281,7 +2295,7 @@
"for IBSS beacon\n", dev->name);
break;
}
- control.tx_rate = (local->short_preamble &&
+ control.tx_rate = (sdata->short_preamble &&
(rate->flags & IEEE80211_RATE_PREAMBLE2)) ?
rate->val2 : rate->val;
control.antenna_sel_tx = local->hw.conf.antenna_sel_tx;
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 532cf51..36761c7 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -173,7 +173,7 @@
* to closest integer */
dur = ieee80211_frame_duration(local, 10, rate, erp,
- local->short_preamble);
+ tx->sdata->short_preamble);
if (next_frag_len) {
/* Frame is fragmented: duration increases with time needed to
@@ -182,7 +182,7 @@
/* next fragment */
dur += ieee80211_frame_duration(local, next_frag_len,
txrate->rate, erp,
- local->short_preamble);
+ tx->sdata->short_preamble);
}
return dur;
@@ -627,12 +627,6 @@
tx->u.tx.control->rate = tx->u.tx.rate;
}
tx->u.tx.control->tx_rate = tx->u.tx.rate->val;
- if ((tx->u.tx.rate->flags & IEEE80211_RATE_PREAMBLE2) &&
- tx->local->short_preamble &&
- (!tx->sta || (tx->sta->flags & WLAN_STA_SHORT_PREAMBLE))) {
- tx->u.tx.short_preamble = 1;
- tx->u.tx.control->tx_rate = tx->u.tx.rate->val2;
- }
return TXRX_CONTINUE;
}
@@ -641,6 +635,7 @@
ieee80211_tx_h_misc(struct ieee80211_txrx_data *tx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
+ u16 fc = le16_to_cpu(hdr->frame_control);
u16 dur;
struct ieee80211_tx_control *control = tx->u.tx.control;
struct ieee80211_hw_mode *mode = tx->u.tx.mode;
@@ -677,6 +672,16 @@
!(control->flags & IEEE80211_TXCTL_USE_RTS_CTS))
control->flags |= IEEE80211_TXCTL_USE_CTS_PROTECT;
+ /* Transmit data frames using short preambles if the driver supports
+ * short preambles at the selected rate and short preambles are
+ * available on the network at the current point in time. */
+ if (((fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA) &&
+ (tx->u.tx.rate->flags & IEEE80211_RATE_PREAMBLE2) &&
+ tx->sdata->short_preamble &&
+ (!tx->sta || (tx->sta->flags & WLAN_STA_SHORT_PREAMBLE))) {
+ tx->u.tx.control->tx_rate = tx->u.tx.rate->val2;
+ }
+
/* Setup duration field for the first fragment of the frame. Duration
* for remaining fragments will be updated when they are being sent
* to low-level driver in ieee80211_tx(). */
@@ -1750,7 +1755,7 @@
return NULL;
}
- control->tx_rate = (local->short_preamble &&
+ control->tx_rate = (sdata->short_preamble &&
(rate->flags & IEEE80211_RATE_PREAMBLE2)) ?
rate->val2 : rate->val;
control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
@@ -1765,7 +1770,7 @@
}
EXPORT_SYMBOL(ieee80211_beacon_get);
-void ieee80211_rts_get(struct ieee80211_hw *hw,
+void ieee80211_rts_get(struct ieee80211_hw *hw, int if_id,
const void *frame, size_t frame_len,
const struct ieee80211_tx_control *frame_txctl,
struct ieee80211_rts *rts)
@@ -1775,13 +1780,13 @@
fctl = IEEE80211_FTYPE_CTL | IEEE80211_STYPE_RTS;
rts->frame_control = cpu_to_le16(fctl);
- rts->duration = ieee80211_rts_duration(hw, frame_len, frame_txctl);
+ rts->duration = ieee80211_rts_duration(hw, if_id, frame_len, frame_txctl);
memcpy(rts->ra, hdr->addr1, sizeof(rts->ra));
memcpy(rts->ta, hdr->addr2, sizeof(rts->ta));
}
EXPORT_SYMBOL(ieee80211_rts_get);
-void ieee80211_ctstoself_get(struct ieee80211_hw *hw,
+void ieee80211_ctstoself_get(struct ieee80211_hw *hw, int if_id,
const void *frame, size_t frame_len,
const struct ieee80211_tx_control *frame_txctl,
struct ieee80211_cts *cts)
@@ -1791,7 +1796,7 @@
fctl = IEEE80211_FTYPE_CTL | IEEE80211_STYPE_CTS;
cts->frame_control = cpu_to_le16(fctl);
- cts->duration = ieee80211_ctstoself_duration(hw, frame_len, frame_txctl);
+ cts->duration = ieee80211_ctstoself_duration(hw, if_id, frame_len, frame_txctl);
memcpy(cts->ra, hdr->addr1, sizeof(cts->ra));
}
EXPORT_SYMBOL(ieee80211_ctstoself_get);
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index c456583..091ac0d 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -314,31 +314,46 @@
}
/* Exported duration function for driver use */
-__le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
+__le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, int if_id,
size_t frame_len, int rate)
{
struct ieee80211_local *local = hw_to_local(hw);
+ struct net_device *bdev = dev_get_by_index(if_id);
+ struct ieee80211_sub_if_data *sdata;
u16 dur;
int erp;
+ if (unlikely(!bdev))
+ return 0;
+
+ sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
dur = ieee80211_frame_duration(local, frame_len, rate,
- erp, local->short_preamble);
+ erp, sdata->short_preamble);
+ dev_put(bdev);
return cpu_to_le16(dur);
}
EXPORT_SYMBOL(ieee80211_generic_frame_duration);
-__le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
+__le16 ieee80211_rts_duration(struct ieee80211_hw *hw, int if_id,
size_t frame_len,
const struct ieee80211_tx_control *frame_txctl)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_rate *rate;
- int short_preamble = local->short_preamble;
+ struct net_device *bdev = dev_get_by_index(if_id);
+ struct ieee80211_sub_if_data *sdata;
+ int short_preamble;
int erp;
u16 dur;
+ if (unlikely(!bdev))
+ return 0;
+
+ sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
+ short_preamble = sdata->short_preamble;
+
rate = frame_txctl->rts_rate;
erp = !!(rate->flags & IEEE80211_RATE_ERP);
@@ -352,20 +367,29 @@
dur += ieee80211_frame_duration(local, 10, rate->rate,
erp, short_preamble);
+ dev_put(bdev);
return cpu_to_le16(dur);
}
EXPORT_SYMBOL(ieee80211_rts_duration);
-__le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
+__le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, int if_id,
size_t frame_len,
const struct ieee80211_tx_control *frame_txctl)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_rate *rate;
- int short_preamble = local->short_preamble;
+ struct net_device *bdev = dev_get_by_index(if_id);
+ struct ieee80211_sub_if_data *sdata;
+ int short_preamble;
int erp;
u16 dur;
+ if (unlikely(!bdev))
+ return 0;
+
+ sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
+ short_preamble = sdata->short_preamble;
+
rate = frame_txctl->rts_rate;
erp = !!(rate->flags & IEEE80211_RATE_ERP);
@@ -378,6 +402,7 @@
erp, short_preamble);
}
+ dev_put(bdev);
return cpu_to_le16(dur);
}
EXPORT_SYMBOL(ieee80211_ctstoself_duration);